Comment # 63 on bug 1017461 from Libor Pechacek

(In reply to Jan Ritzerfeld from comment #62)
> Hmm, is this commit included in openSUSE-SU-2017:0907-1?

AFAICT yes: http://kernel.suse.com/cgit/kernel/log/?h=rpm-4.4.57-18.3&ofs=50

Also feel free to inspect the package change log (rpm -q -changelog
kernel-default-4.4.57-18.3.1), which should contain a record named "btrfs:
backref: Fix soft lockup in __merge_refs function" and a reference to this
Bugzilla.

> Sure, but that doesn't work because a "snapper cleanup number" then says
> "quota not working (preparing quota failed)".

I see. I didn't know about these dark corners. Is that perhaps something for a
bug report?